This research work was to study the effect of surface treatment of natural fiber and the effects of type and content of natural fiber on the development of acoustic material from natural rubber foam /natural fiber composites. The surface treatment used for this research work was sodium hydroxide (NaOH) treatment. NaOH Concentrations and treatment times were varied from 0 to 15 %wt. and 0 to 30 min respectively. Natural fibers used for this work were bagasse fiber (BF) and oil palm fiber (OPF). The suitable condition for surface treatment was estimated by fiber length and diameter (L/D) ratio and morphology of natural fiber. The result suggested that L/D ratios tended to increase when NaOH concentrations and/or treatment times increased except for NaOH concentration of 15 %wt. L/D ratios of OPF after surface treatment were changed more than those of BF. The suitable conditions of NaOH treatment for BF and OPF were NaOH concentration of 10 %wt. and surface treatment times of 30 and 10 min respectively. The effects of fiber type and content on sound absorption properties of natural rubber foam /natural fiber composites were investigated by cell characteristics sound absorption coefficient DMA analysis and bulk density. Both treated BF and OPF with suitable treatment condition were varied from content of 0.0 to 10.0 %wt. The result showed that the cell size of composites tended to decrease with addition of natural fiber whereas number of foam cell per unit volume increased. After adding natural fiber more than 2.5 %wt. cell size of composite foam and number of foam cell per unit volume tended to change the inverse direction. Natural fiber in composites enhanced the sound absorption efficiency. Sound absorption coefficient of composites adding BF was more than that of composite adding OPF. The addition of natural fiber enhanced the elasticity of composites and that increased sound absorption efficiency. NaOH treatment led to creation of strong interfacial bonding between natural fiber and natural rubber and enhanced the sound absorption efficiency. Density of NR composite foam increased with increasing natural fiber content.

This research aims to study the properties of natural rubber STR 20 at 100 phr with various contents of coir (e.g. 0 5 10 20 40 and 80 phr) and then mixed with chemical substance at constant ratio. After that the samples are ground by two-roll mill and formed by compression molding at 150 degree Celsius. This leads into the coir reinforcement natural rubber plate of dimension 30x30x0.5 cm. The properties of the natural rubber plates are tested under ASTM standard. From the results it is found that increasing in coir then the properties of resilience and density are improved at every mix ratio. However the tensile strength tear strength and wearing are increased at some certain value of coir. The samples give no water absorption at every mix ratio. The results from this research indicate that it can develop into the rubber floor tiles and rubber wall tiles for furnishing the buildings in natural style.

The natural rubber with silica masterbatch was produced and used as based material in rubber compound modified from standard tread formulation given in ASTM E 1136. The reduction of mixing energy and rubber vulcanizate properties were investigated. Results indicate that in comparison with STR 5L compound the rubber with silica masterbatch i.e. fresh latex (FNRmSi) low viscosity natural rubber used 1.0 phr of hydrogen peroxide (LNR1mSi) and low viscosity natural rubber used 0.34 phr of hydrogen peroxide and 2.7 phr of potassium persulphate mixture (LNR2mSi) provides maximum mixing energy saving of 30.48% 33.37% and 37.20% respectively. The scorch time and cure time rise with increasing filler loading. The mechanical properties of LNR1mSi and LNR2mSi are similar to those STR5L compound whereas FNRmSi vulcanizate shows superior mechanical properties such as 300% modulus tear resistance abrasion resistance elongation at break and tensile strength. The homogenous distribution and interfacial interaction of silica filler and natural rubber matrix were enhanced by the self-assembled silica masterbatch as shown by the fracture surfaces morphology of the vulcanizate using a Scanning Electron Microscope (SEM). The silica masterbatch form has reduced the mixing power consumption and enhanced the mechanical properties.

The reduction of calcium carbonate (CaCO3) particle was prepared by wet grinding method with 40% dispersion. The particle sizes of CaCO3 were studied with various time of wet grinding. It was found that the particle sizes of CaCO3 rapidly decreased in 3 day of grinding after that it was slightly reduce. Therefore the CaCO3 at various time of wet grinding were mixed with concentrate latex (60% dry rubber content DRC). The result showed that the wet grinding for 2 days provided the superior machanical properties. In addition the compound with epoxidized natural rubber (ENR) as a coupling agent was investigated. It was found that the 5 phr of 30% mole percent of ENR results in significantly improved mechanical properties of the rubber vulcanizates.

This research presents the engineering properties of asphalt (AC 60/70) modified with different ratios of scrap natural rubber. Then select the best properties of the binder to mix asphaltic concrete. From laboratory testing results with adding 7% scrap natural rubber into mixtures for the best results. The properties of asphaltic concrete can be improved by adding 7% scrap natural rubber. For asphaltic concrete Marshall Stability increased with adding scrap natural rubber into asphalt. Moreover the stiffness modulus of asphaltic concrete can be improved 13.53 compared to AC 60/70.